Axial compression enhanced tubular expansion

ABSTRACT

Methods and apparatus for expanding a tubular with the aid of a compressive force are disclosed. A tubular is run into a wellbore. While the tubular is in a compressive state, the tubular is expanded into its desired form. The expanded tubular can be used for multiple downhole functions such as completing multilateral junctions in a wellbore, patching apertures in a wellbore and lining a wellbore.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the invention generally relate to expanding tubulars in awellbore. More particularly, embodiments of the invention relate to theexpansion of the tubulars enhanced by use of compressive forces appliedto the tubulars.

2. Description of the Related Art

Hydrocarbon and other wells are completed by forming a borehole in theearth and then lining the borehole with pipe or casing to form awellbore. After a section of wellbore is formed by drilling, a sectionof casing is lowered into the wellbore and temporarily hung therein fromthe surface of the well. Using apparatus known in the art, the casing iscemented into the wellbore by circulating cement into the annular areadefined between the outer wall of the casing and the borehole. Thecombination of cement and casing strengthens the wellbore andfacilitates the isolation of certain areas of the formation behind thecasing for the production of hydrocarbons.

Recent developments in the oil and gas exploration and extractionindustries have included using expandable bore lining tubing. Apparatusand methods are emerging that permit tubulars to be expanded in situ.The most common expansion apparatus is a cone or a swedge. Someexpansion apparatus include expander tools which are fluid powered andare run into the wellbore on a working string. These hydraulic expandertools can include radially extendable members which, through fluidpressure, are urged outward radially from the body of the expander tooland into contact with a tubular therearound. As sufficient pressure isgenerated on a piston surface behind these extendable members, thetubular being acted upon by the expansion tool is expanded past itspoint of plastic deformation. In this manner, the inner and outerdiameter of the tubular is increased in the wellbore. By rotating theexpander tool in the wellbore and/or moving the expander tool axially inthe wellbore with the extendable members actuated, a tubular can beexpanded along a predetermined length in a wellbore. Other methodsinclude using hydraulic pressure inside the tubular to expand thetubular past its point of plastic deformation.

Multiple uses for expandable tubulars are being discovered. For example,an intermediate string of casing can be hung off a string of surfacecasing by expanding a portion of the intermediate string into frictionalcontact with the lower portion of surface casing therearound. Thisallows for the hanging of a string of casing without the need for aseparate slip assembly. Additional applications for the expansion ofdownhole tubulars exist. These include the use of an expandable sandscreen, employment of an expandable seat for seating a diverter tool,and the use of an expandable seat for setting a packer.

There are problems associated with the expansion of tubulars. Oneparticularly associated with rotary expander tools is that the rotaryexpansion of the tubular makes the wall of the tubular thinner. Thisthen increases the overall length of the tubular which is problematicwhen trying to determine location in the well. Further, expandabletubulars are currently limited to an expansion of 10%-25% of theiroriginal diameter using existing expansion techniques that areconstrained by the tubular burst pressure and friction applied thereto.Also when using hydraulic pressure to expand the tubular, due to thehigh pressure required, weaknesses in the tubular are exploited limitingthe amount of expansion that can be achieved before the tubularruptures.

There exists a need for an improved method and apparatus for expandingcasing or other tubulars within a wellbore. Further, there exists a needfor method and apparatus for expanding a tubular which requires lessoutward force or hydraulic pressure on the tubular with increasedexpansion. There exists yet a further need for an apparatus and methodfor expanding a tubular which reduces the risk of uneven expansion ofthe tubular by reducing the amount of force needed for the expansionoperation. Further, there exists a need for a method of expanding atubular and accurately controlling the location of the tubing.

SUMMARY OF THE INVENTION

Embodiments of the invention generally relate to methods and apparatusfor expanding tubulars in a wellbore enhanced by compressive forceapplied to the tubulars. According to one aspect of the invention, amethod of expanding a tubular in a wellbore includes positioning thetubular in the wellbore, affixing at least two locations spaced along alength the tubular to desired locations in the wellbore, and expanding aportion of the tubular between the two locations outward radially with arotary expander tool, such that the tubular is in compression whileexpanding. According to another aspect of the invention, methods andapparatus provide for expanding a tubular run into a wellbore byapplying a compressive force to at least a portion of the tubular andapplying fluid pressure to an inside surface of the tubular to expandthe tubular to a larger diameter. The tubular can be located proximateto a window in the wellbore such that expanding the compressed portionof the tubular covers the window and may form a bulge extending throughthe window.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments thereof which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 is a sectional view of a wellbore having a tubular disposedtherein for expansion according to aspects of the invention;

FIG. 2 is a sectional view of a tubular and an expansion assemblyattached to a work string and disposed in a wellbore;

FIG. 3 is a sectional view of the tubular of FIG. 2 after expansion withhydraulic pressure applied to an inside surface thereof;

FIG. 4 is a sectional view of the tubular of FIG. 2 after completingexpansion with hydraulic pressure;

FIG. 5 is a sectional view of the tubular of FIG. 4 after being expandedin a wellbore with a multilateral junction;

FIG. 6 is a sectional view of the tubular of FIG. 5 after being fullyexpanded;

FIG. 7 is a sectional view of the multi-lateral junction of FIG. 5completed with the tubular expanded and drilled out; and

FIGS. 8 to 11 are schematic illustrations of steps in the process oflining a bore in accordance with embodiments of the invention.

DETAILED DESCRIPTION

FIG. 1 illustrates a cross-sectional view of a wellbore 100 and atubular 110 disposed therein. The tubular 110 can be casing or any othertype of tubular used in downhole drilling operations, such as a liner ora patch. First and second fixed locations 120, 130 spaced apart alongthe length of the tubular 110 substantially prevent axial movement ofthe tubular 110 in the wellbore 100 such that the distance between thefixed locations 120, 130 cannot vary. The fixed locations 120, 130 canbe achieved by any method or combination of methods known in the art,such as by using anchors or slips on an outside of the tubular 110 toengage a surrounding surface, by selectively expanding the tubular 110at one or both of the fixed locations 120, 130 into frictional contactwith the surrounding surface or by locating the bottom of the tubular110 on a stop such as a plug, a packer or a bottom of the borehole (see,FIGS. 9-12). In the embodiment shown in FIG. 1, the fixed locations 120,130 have been expanded to place the outside surface of the tubular 110into contact with a surrounding surface. Expansion of the fixedlocations 120, 130 can be performed by either using a rotary expandertool 140 or additional expander(s) (not shown), such as one or moreinflatable members or packers, capable of selective expansion at thefixed locations 120, 130. The fixed locations 120, 130 create an annularspace between the tubular 110 and the wellbore 100. To facilitateexpansion of the tubular 110, fluid in the annular space can escapethrough apertures (not shown) in a surrounding casing and into aformation, through apertures in the tubular 110, across flow paths atone or both of the fixed locations 120, 130 such as by only partialcircumferential expansion, and/or directly into the surroundingformation when in an open wellbore. For example, the tubular 110 mayserve as a patch to remedy excessive mud loss in an open hole such thatfluid from the annular space can easily be pushed into the formation.

U.S. Pat. No. 6,457,532, which is herein incorporated by reference inits entirety, discloses an exemplary rotary expander tool that can beused as the rotary expander tool 140 schematically illustrated inFIG. 1. The rotary expander tool 140 operates to expand the length ofthe tubular 110 between the fixed locations 120, 130. Typically, therotary expander tool 140 starts at one fixed location (e.g., the firstfixed location 120) and progresses to the other fixed location (e.g.,second fixed location 130) expanding the tubular 110 along the way. Ifonly one location along the tubular is initially fixed, expansion canstart a distance from that location to thereby provide the other fixedlocation prior to the rotary expander tool 140 moving toward theinitially fixed location. The tubular need not be placed in compressionprior to starting expansion of the tubular 110 between the two fixedlocations 120, 130 since a compressive load in the tubular 110 developsas expansion with the rotary expander tool 140 progresses. This is dueto the fact that use of the rotary expander tool 140 lengthens thetubular 110 by thinning of the tubular wall which, because the fixedlocations 120 130 are set to prevent the elongation of the tubular 110,compresses the tubular 110. In contrast, a cone used to expand a tubulartypically causes the tubular to shorten during expansion such thattension and not compression develops if the cone is used to expand asection between two fixed locations. The compression in the tubular 110enhances the expansion process by increasing the expansion possible anddecreasing the amount of force required by the rotary expander tool 140.

Before both of the two fixed locations 120, 130 are set, the tubular 110can optionally be placed in compression either through use of gravity ora mechanical, electrical, or hydraulic device adapted to apply acompressive load on the tubular. Since the tubular 110 is expandedbetween end points that are fixed, this increases accurate location ofthe tubular 110 in the wellbore 100. Thus, this process enables accurateplacement of liners, patches and other tubulars in the wellbore withoutthe side effects of having the liner elongate or shorten duringexpansion.

FIG. 2 shows a section of the wellbore 100 with a liner 230 andexpandable tubing 200. The expandable tubing 200 can be casing, liner, apatch, or any other type of tubing used in downhole operations forexpansion into the liner 230, casing or an open wellbore. FIG. 2 depictsthe expandable tubing 200 as a patch used for closing an aperture 235 inthe wellbore 100 that is lined. The patch can include a seal 256 and ananchoring element 257 on the outside of the expandable tubing 200.

The expandable tubing 200 attaches to a work string 210 via a settingtool 220. The lower end of the expandable tubing 200 attaches to thework string 210 by a carrying mechanism 240 of the setting tool 220. Thecarrying mechanism 240 is any suitable temporary connection known in theart such as carrying dogs, collets, threads, latches, slips etc. In oneembodiment the carrying mechanism 240 is a set of pre-set slips 231. Thepre-set slips 231 engage the inside diameter of the expandable tubing200 with a series of teeth 232. The pre-set slips 231 support the weightof the expandable tubing 200 and the piston assembly. The pre-set slips231 are held in place by wedges 233 and 234. Wedge 234 is fixedlyattached to the work string 210. Wedge 233 is attached to a slip releaseassembly 236. The slip release assembly 236 connects to a seat 237. Theseat 237 holds a sealing member such as a dart, or ball 270 at its upperend in order to hydraulically seal the work string 210. The seat 237connects to the work string 210 with a shear pin 238. Above the pre-setslips 231 is a lower pressure seal cup 239 for hydraulically sealing theinterior of the expandable tubing 200. At the upper end of theexpandable tubing 200, a compression piston 250 of the setting tool 220attaches the expandable tubing 200 to the work string 210. Thecompression piston 250 has a shoulder 253 which engages the upper end ofthe expandable tubing 200. The compression piston 250 moves relative tothe work string 210 and a piston base 251. The piston base 251 fixedlyattaches to the work sting 210, thus as fluid flows in to an annulus252, the piston 250 pushes the expandable tubular 200 down relative tothe work string 210. With the lower end of the expandable tubular 200fixed to the work string 210 by carrying mechanism 240, the expandabletubular 200 is in compression. More than one compression piston can beused in order to increase the compressive force applied to theexpandable tubing 200, as is known in the art. The carrying mechanism240 and the compression piston 250 can be adapted to seal the top andbottom of the expandable tubing 200.

As illustrated in FIG. 3, the work string 210 lowers into the wellbore100 to a desired location for the expandable tubing 200. Once at thedesired location, the compression piston 250 actuates upon applicationof hydraulic pressure through the work string 210, which can beselectively plugged by a stopper, such as a ball 270 dropped onto theseat 237, a diverter valve such as that disclosed in U.S. patentapplication Ser. No. 10/954,866 assigned to Weatherford/Lamb, Inc. whichis hereby incorporated by reference, could also be used. The compressionpiston 250 urges the attached top of the expandable tubing 200 towardthe carrying mechanism 240. This places the expandable tubing 200 incompression since the attachment of the top of the expandable tubing 200via the compression piston 250 permits relative movement between thework string 210 and the expandable tubing 200 while the attachment ofthe expandable tubing 200 at the carrying mechanism 240 preventsrelative axial movement between the lower end of the expandable tubingand the work string 210. Simultaneously, hydraulic pressure providedthrough port 245 acts on an inside surface of the expandable tubing 200to cause radial expansion of the expandable tubing 200 along a length ofthe expandable tubing 200 between the lower pressure seal cup 239 and anupper pressure seal cup 254.

The expandable tubing 200 can utilize changes in material andconfiguration in order to enhance expansion. In one embodiment, thetubing thickness at the two fixed end points, the piston 250 andcarrying mechanism 240 is larger that the expandable tubing 200 wallthickness between the fixed points. Further, in another embodiment theyield strength and/or elastic modulus of the expandable tubular 200 ischanged between the fixed points. In another embodiment the expandabletubular 200 is longitudinally corrugated between the fixed points. Inyet another embodiment the expandable tubular 200 has a differentmaterial than the material at the fixed points. Further, any of thesemethods can be used in combination to enhance expansion of theexpandable tubular 200. These embodiments ensure the expandable tubular200 expands from the middle portion first and then outwards toward bothends. This ensures that fluids are not trapped in the annulus betweenthe Expandable tubular 200 and the liner 230.

After expansion of the expandable tubing 200 with hydraulic pressure itis necessary to ensure the expandable tubular 200 is secure in thewellbore by pulling or pushing on the work string 210. The setting tool220 then releases the expandable tubular 200 at the carrying mechanism240. By increasing the hydraulic pressure in the work string 210 theseat 237 shears the shear pin 238. This causes the slip release assembly236 to move down which moves the lower wedge 233 down, releasing thepre-set slips 231 as shown in FIG. 4. Additionally, an expander 265(shown schematically) actuates to an extended position having anincreased outer diameter. The expander 265 can be any type of expandablecone or hydraulically actuated rotary expander tool, such as thosedisclosed in U.S. Pat. No. 6,457,532, U.S. patent application Ser. No.10/808,249 and U.S. patent application Ser. No. 10/954,866, which arehereby incorporated by reference.

FIG. 4 shows the expandable tubing 200 while the expander 265 completesexpansion of the expandable tubing 200 along its entire length. Inoperation, lowering the work string 210 moves the expander 265 throughthe expanded section of the expandable tubular 200 and across the end ofthe expandable tubular 200 where expansion was previously prevented bythe carrying mechanism 240. As the expander 265 moves through theexpandable tubular 200, the expander 265 insures proper expansion and/orfurther expands the previously expanded length of the expandable tubular200 and expands the bottom end of the expandable tubular 200.Accordingly, the previously unexpanded top end of the expandable tubular200 where expansion was previously prevented due to attachment to thecompression piston 250 occurs upon pulling the expander 265 out of theexpandable tubular 200 during removal of the work string 210. For someembodiments, the expander 265 may not be required if it is not desiredto expand the ends of the expandable tubular 200 where the expandabletubular attaches to the setting tool 220. Further, the expander 265 canbe arranged to work in conjunction the hydraulic expansion in order toenhance the expansion process. Further, the expander 265 can be attachedeither below or above the expandable tubular 200 or on another tool andactuated once hydraulic expansion is complete. The work string 210 isremoved upon completion of the expansion leaving the expandable tubing200 in place. Thus, the expandable tubing 200 can be used to patchapertures in the casing, liner or the wellbore itself with no liner. Inanother embodiment, the unexpanded portions of the expandable tubular200 could be removed by the apparatus and methods disclosed in U.S. Pat.No. 6,598,678 assigned to Weatherford/Lamb, Inc. or as disclosed U.S.Pat. No. 6,752,215 assigned to Weatherford/Lamb, Inc which are herebyincorporated by reference. This procedure can be done multiple times inthe wellbore in order to control production from the formations.

FIGS. 5-7 depict an embodiment of the invention that utilizes anassembly similar to that illustrated in FIGS. 2-4. FIG. 5 shows thewellbore 100 with a window 310 cut in the side to provide an opening fora lateral junction 320. An expandable tubing 300 is shown expanded sothat it covers the lateral junction 320. The expandable tubular 300expands using the methods described above. Thus, the expandable tubing300 is compressed. While in compression, the expandable tubing 300 isexpanded by fluid pressure acting on an inside surface of the expandabletubing to initially expand the expandable tubing 300 up to an innerdiameter of the wellbore 100, as shown in FIG. 5. The expansion processcontinues by further application of hydraulic pressure to cause a wallof the expandable tubing 300 to bulge at the window 310 and enter thelateral junction 320, as shown in FIG. 6. For enhanced expansion, theexpandable tubing may comprise any suitable material which can sustainan expansion ratio of greater than 20%. Further, the expandable tubingcan be initially longitudinally corrugated in order to facilitate a highexpansion ratio. The expander 265 is removed from the wellbore. Thelateral junction 320 can then be drilled out using techniques known inthe art providing a multi-lateral junction, as shown in FIG. 7. Asubsequent liner (not shown) can be run into the lateral junction 320and suspended off of the tubing 300 therein.

FIGS. 8-11 depict an embodiment of the invention used to line a wellbore400. FIG. 8 shows the lower end of the wellbore 400 including an unlinedbore section 410. Above the unlined section 410, casing 420 lines thewellbore 400. As shown, the lower end of the casing 420 includes alarger diameter end section 425, or bell-end, however, the lower end ofthe casing 420 can be straight pipe.

An expandable tubing or liner 430 is run into the wellbore 400 on a workstring 440. The liner 430 is initially coupled to the work string 440via a setting tool 450. The liner 430 is located in the wellbore 400such that the upper end of the liner 430 overlaps the larger diametercasing end section 425. The lower end of the liner 430 is positioned atthe end of the wellbore 400. The liner 430 itself or a shoe 460 contactsthe bottom of the wellbore 400. Next, weight can optionally be set downon the liner 430. The weight can be from the length of the work string440, or any other method that places the liner 430 in a compressivestate.

As shown in FIG. 9, once the liner 430 is in compression, an anchor 470is set. The anchor 470 can be any type of liner hanger known in the art.With the anchor 470 set, the liner 430 is held in compression betweenthe anchor 470 and the end of the wellbore 400. For some embodiments,the compressive state, as discussed above with regard to FIG. 1, may becaused solely by the expansion process itself and not initially appliedto the liner 430 prior to setting of the anchor 470.

Next, as shown in FIG. 10, a rotary expander tool 480 moves downwardlythrough the liner 430 to expand the liner 430 to a larger diameter suchthat the expanded inner diameter of the liner 430 corresponds to theinner diameter of the casing 420. A more detailed description of thesetting tool and expansion tool can be found in U.S. Patent ApplicationPublication No. 2003/0127225, which is herein incorporated by referencein its entirety. The compressive state of the liner 430 enhances theexpansion process and requires less force from the rotary expander tool480 than conventional methods. Once the desired expansion of the lineris complete, the liner 430 can be cemented in place, and the annulusbetween the liner 430 and the casing 420 proximate the anchor 470 can besealed.

FIG. 11 shows creation of a bulge formed monobore shoe, which can be anadditional step to the method described in FIGS. 8-10. Once the liner430 is on the bottom of the wellbore 400, weight is applied to the liner430 to place the liner 430 in compression. The bottom of the liner 430is then expanded by fluid pressure applied to the inner surface of theliner 430 to form a bell shaped end 500. For some embodiments, thematerial used at the bell shaped end 500 of the liner 430 has a thinnerwall thickness than the rest of the liner 430 and/or is shaped pipe inorder to facilitate expansion thereof and provide the bell shaped end500 upon expansion. Further, the bell shaped end 500 may behydraulically isolated from the rest of the liner such that the fluidpressure is applied to only the bell shaped end 500. Additional bellshaped ends (not shown) having smaller diameters than the bell shapedend 500 may be located above the bell shaped end 500. These additionalbell shaped ends may be formed by application of a different fluidpressure than applied to the bell shaped end 500 and/or they may beformed of a different material than the bell shaped end 500. Theremainder of the liner 430 can be expanded using any expansion methodsuch as a rotary expansion, a swedge or cone, hydraulic pressure and anymethods described above.

Any of the expandable tubing described above can be longitudinallycorrugated tubing or shaped pipe in order to further facilitateexpansion. Using shaped pipe or corrugated tubing also reduces thetendency for pipe to buckle. This allows for compression of longerlengths of pipe enhancing the expansion process further.

Further, the methods described above can be used in any type of downhole tubular expansion including but not limited to liner hangers,packers, straddles, PBRs, drilling-with-liner, etc.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A method of expanding a tubular in a wellbore, comprising:positioning the tubular in the wellbore; affixing at least first andsecond locations spaced along a length of the tubular to desiredlocations in the wellbore; and expanding a portion of the tubularbetween the locations outward radially with a rotary expander tool, suchthat the tubular is in axial compression while expanding.
 2. The methodof claim 1, wherein affixing the second location includes supporting alower end of the tubular on a bottom of the wellbore.
 3. The method ofclaim 1, wherein affixing the at least first and second locationsincludes expanding the tubular into frictional contact with asurrounding surface.
 4. The method of claim 1, wherein affixing the atleast first and second locations includes setting slips on an outersurface of the tubular.
 5. The method of claim 1, wherein affixing thesecond location includes supporting a lower end of the tubular on aplug.
 6. The method of claim 1, wherein the tubular is longitudinallycorrugated.
 7. The method of claim 1, wherein the tubular includesshaped pipe.
 8. The method of claim 1, wherein the compression is atleast partly as a result of the expanding.
 9. A method of lining adrilled wellbore, comprising: running a tubular into a wellbore;applying a compressive force to at least a portion of the tubular; andapplying fluid pressure to an inside surface of the tubular in an areaof the tubular that is in compression to expand the tubular to a largerdiameter.
 10. The method of claim 9, further comprising supporting alower end of the tubular on a bottom of the wellbore.
 11. The method ofclaim 10, wherein applying the compressive force includes placing weighton an upper end of the tubular.
 12. The method of claim 9, whereinapplying the compressive force includes operating a compressive forceapparatus.
 13. The method of claim 9, wherein applying the fluidpressure to the inside surface of the tubular expands a lower portion ofthe tubular into a bell shaped configuration.
 14. The method of claim 9,wherein running the tubular includes positioning the tubular in thewellbore proximate to a window in the wellbore.
 15. The method of claim14, wherein applying the fluid pressure to the inside surface of thetubular forms a bulge in a wall of the tubular that extends into alateral junction which starts at the window.
 16. The method of claim 15,further comprising drilling out a portion of the wall of the tubularthat is extended into the lateral junction.
 17. The method of claim 16,further comprising hanging a liner from the tubular extended into thelateral junction.
 18. An apparatus for wellbore completion, comprising:a tubular coupled to a conveyance member; one or more compressionpistons for applying a compressive load to at least a length of thetubular; and first and second seals for isolating an inside of thetubular corresponding to at least a portion of the length of the tubularhaving the compressive load applied thereto, wherein a port to theinside of the tubular supplies hydraulic pressure for acting on a innersurface of the tubular and expanding the tubular.
 19. The apparatus ofclaim 18, further comprising a radially extendable expander forexpanding sections of the tubular proximate the first and second seals.20. The apparatus of claim 18, wherein the tubular is longitudinallycorrugated.
 21. The apparatus of claim 18, wherein the tubular is shapedpipe.
 22. A method of expanding a tubular in a wellbore, comprising:positioning the tubular in the wellbore; applying a compressive force toat least a portion of the tubular; and expanding the portion of thetubular in compression outwardly, wherein expanding includes translatingan expansion tool axially while the tubular is in compression.